Plasma fluorination of organosilicon polymeric films for gas separation applications

• Published in: Journal of membrane science Vol. 125; no. 2; pp. 319 - 329
• Main Authors: Borisov, S., Khotimsky, V.S., Rebrov, A.I., Rykov, S.V., Slovetsky, D.I., Pashunin, Yu.M.
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 19.03.1997
• Subjects: Fluorination; Gas separation; Nuclear magnetic resonance spectroscopy; Plasma modification; Polytrimethylsilylpropyne; Polyvinyltrimethylsilane; X-ray photoelectron spectroscopy; Polytrimethylsilylpropyne; Gas separation; Polyvinyltrimethylsilane; Nuclear magnetic resonance spectroscopy; Fluorination; X-ray photoelectron spectroscopy; Plasma modification
• ISSN: 0376-7388; 1873-3123
• DOI: 10.1016/S0376-7388(96)00254-2

SF 6 plasma treatment using an RF discharge was carried out for the surface fluorination of polytrimethylsilylpropyne (PTMSP) and polyvinyltrimethylsilane (PVTMS) films. Gas permeation of the fluorinated and untreated films for O 2, N 2, He, H 2, CH 4 and CO 2 gases has been measured. Plasma fluorination increases the ideal selectivities of the PTMSP films decreasing their permeances for all the gases measured, and does not affect the permeances and selectivities of the PVTMS films. The composition and chemical structure of the fluorinated polymer surface were investigated using X-ray photoelectron spectroscopy (XPS) and 19F nuclear magnetic resonance (NMR) spectroscopy. Within the range of the treatment parameters studied, permselectivity and surface composition of the fluorinated PTMSP films depend slightly on the treatment time and the density of the fluorine atom flux on the modified surface. The trimethylsilyl substituents are detached and carbon atoms are partially fluorinated during modification. The structure of the fluorinated layer contains crosslinks and unsaturated bonds.